Telegraph repeater



Jan. 13, 1953 2,625,609

F. H. HANLEY TELEGRAPH REPEATER Filed May 15, 1951 POLAR/ZED\ /Nl/EN7ORBy F. H. HANL EV r4. 2: ATZZORA/EV Patented Jan. 13, 1953 TELEGRAPHREPEATER Frank H. Hanley, Butler, N. J assignor to American Telephoneand Telegraph Company, a corporation of New York Application May 15,1951, Serial No. 226,509

Claims.

This invention relates to telegraph systems and more particularly to animproved telegraph repeater.

As is well known certain types of direct-current magnetic relayrepeaters have receiving relays which are equipped with so-calledvibrating windings to increase the speed of the relay armature intransition between contacts. Such relays are subject to a difficulty inthat if the line between repeater stations is either opened ordisconnected from the receiving relay, the relay armature will vibrate.This vibration, if unobserved, will continue indefinitely causing therelay contacts to deteriorate, at least, if not more serious difliculty.

An object of the present invention is to prevent the abnormal armaturevibration of certain telegraph relays under certain conditions.

A feature of the invention is a protective circuit connected to thewindings of a telegraph receiving relay which is equipped with vibratingwindings to prevent abnormal vibrations of the relay armature.

This and other features of the invention may be understood from thefollowing detailed description when read with reference to theassociated drawing, which taken together disclose two preferredembodiments in which the invention is presently incorporated. It is tobe understood, however, that the invention may be incorporated in otherembodiments which will be suggested from a consideration of thefollowing by those skilled in the art.

In the drawing Fig. 1 shows the antivibrating circuit of the inventionapplied to a polar receiving telegraph relay equipped with vibratingwindings; and Fig. 2 shows a second embodiment of the invention.

It is to be understood that when the values of constants, such as themagnitudes of potentials, resistances, etc., are mentioned in thefollowing, they are given by way of example only, and are not to beconsidered as limitations in the mode of operation of the circuit.

Refer now to Fig. 1 which shows a polar telegraph receiving relay R anda polar telegraph sending relay S interconnected to form a directcurrenttelegraph repeater. The receiving relay R is equipped with fourwindings, 2|, 22, 23 and 2d. The receiving relay R is connected by meansto two metallic conductors l and 2 to a telegraph repeater at a distantstation, say to the west. The sending relay S is connected by a singleconductor 3 to a telegraph repeater at a distant station, say to theeast. Metallic conductor i extends through winding 2| of relay R andmetallic conductor 2 extends through winding 22 of relay R and the twoconductors are then joined at junction 6. At the distant station theconductors pass through telegraph switching means, such as relaycontacts, and are connected to the opposite terminals of a battery, sothat current flows around the loop formed by conductors I and 2 in afirst direction for the marking or steady idle condition. In response tothis the armature of relay R is actuated to engage its right-hand ormarking contact M. For a spacing condition the switches at the distantterminal are actuated to reverse the polarity of the battery connectedto conductors I and 2 and in response to this the armature of relay R isactuated to engage its left-hand Or spacing contact.

When the armature of relay R is in engagement with its right-hand ormarking contact, a circuit may be traced from negative battery I throughthe right-hand or marking contact and armature of relay R and resistanceIt to apex I5 where it branches. One branch extends through the top orline winding of relay S and conductor 3 to the distant east stationwhere it passes through a telegraph repeater and terminates, it will beassumed in positive battery. The other branch extends through the bottomor biasing winding of relay S and resistance It to ground. For thiscondition the efiect of the current flowing in the top winding of relayS tends to actuate the armature of relay S to engage its righthand ormarking contact and this effect is dominant over the counterefifect ofthe current in the bottom or biasing winding of relay S, so that thearmature of relay S engages its right-hand or marking contact. When thearmature of relay R is actuated to engage its spacing contact no currentflows through the line winding of relay S and the effect of current inthe bottom winding of relay S is reversed so that the armature of relayS remains in engagement with its righthand or marking contact. When aspacing signal is transmitted from the eastern terminal, conductor 3 isterminated thereat in negative battery. No current flows through the topwinding of relay S for this condition and its armature engages itsspacing contact under the effect of current flowing from negativebattery on the marking contact of relay R through the bottom winding ofrelays S.

Relay R is equipped with a vibrating circuit connected to its windings23 and 2d the function of which is to speed up the transition of itsarmature when moving between contacts.

When the armature of relay R is in engagement with its marking contact acircuit may be traced from negative battery 1 through the markingcontact and armature of relay R, junction 8 and resistance to parallelbranches. One branch extends through resistance H and winding 23 ofrelay R to ground. The other branch extends through capacitance I2 andwinding 24 to ground. It will be assumed that steady state conditionshave been attained. Current from the negative battery 1 will be flowingthrough resistance ll and the right-hand terminal of condenser [2 willbe charged negatively. The eiTect of the current flowing through winding22 will be tending to actuate the armature of relay R. to engage withits left-hand or spacing contact. At the instant that the armature ofrelay R breaks from its marking contact there will be a rush of currentof negative polarity from condenser I2 through resistance II and winding23 the effect of which will accelerate the armatures of relay R towardthe spacing contact. On the opposite transition the polarity of thecurrent will be changed and the effect will accelerate the armaturetoward the marking contact.

If now the loop through conductors l and 2 is opened or if, as is thecase in practice, the repeater is at times removed from service andconductors l and 2 are disconnected from windings 2! and 22 the armatureof receiving relay R will be under the influence of windings 23 and 24only.

When the armature of relay R engages its marking contact the effect ofthe current from battery i in winding 23 will actuate the armature ofrelay R'to its spacing contact. Condenser 12 will accelerate thetransition. When the arms.- ture of relay R engages its spacing contactthe effect of the current from positive battery 5 will actuate thearmature of relay R toward its marking contact. Condenser 52 willaccelerate the transition. The relay will vibrate continuously underthis condition.

The arrangement of the present invention prevents the abnormal vibrationof relay R. The protection circuit in the present embodiment comprisesthe well known three element gas discharge tube 25 having two gaps, acontrol gap 25 between control element 2? and cathode 28 and a main gap25 between cathode element 28 and anode element 38. The control element21 is connected, the potential between junction 4 and ground will besubstantially one-half of the potential of the battery connected betweenconductors l and 2 at the distant station. The potential of this batterymay be positive 34 volts for the marking condition so that the potentialof points 4 and It may be positive 17 volts with respect to ground. Thepotential of element 28 may be for instance positive 2 volts withrespect to ground. The potential across control 23 is thereforeapproximately 15 volts which is too low to ionize the control gap, whichrequires about '70 volts.

When the loop formed by conductors i and 2 is disconnected or opened,the armature of relay R will start to vibrate abnormally. Positive 130volts is impressed through the 1.5 megohm resistor 5 between elements 21and 28 ionizing control gap 26. When the armature of relay R engages itsspacing contact a circuit is established from positive battery 6 throughthe spacing contact and armature of relay R, resistance 9, anode element3!], gap 29, cathode element 28 and winding 24 to ground. The effect ofthe current flowing in winding 24 of relay R due to the ionization ofthe main gap of tube 25 looks the armature of relay R. to its spacingcontact, preventing further vibration.

In the arrangement per Fig. 2 the invention is shown applied to a fullmetallic repeater having an auxiliary receiving relay and arrangedslightly differently than the arrangement per Fig. 1. With respect tothe present invention, however, the essential difference is in thearrangement of the circuit connected to the anode 30 of tube 25. In Fig.2 the voltage applied to the anode 38 is obtained from a potentiometer,formed by resistances RI and R2 which are equal. The potentials appliedto the marking and spacing contacts are negative and positive 48 voltsfor instance and the potential connected to the lower terminal of R2 ispositive volts. When the R relay is in the marking condition thepotential applied to the anode 39 will be approximately positive 41volts, one-half the difierence between negative 48 and positive 130volts, and when the R relay is spacing the potential will be one-halfthe sum of positive 48 and positive 130 volts or positive 89 tion, saidcircuit comprising a space discharge device responsive to a condition ofsaid relay tending to produce said abnormal vibration and armatureholding means on said relay responsive to said space discharge device.

2. In a telegraph system, a polar telegraph receiving relay having anarmature, a line winding and a vibrating winding for vibrating saidarmature, said relay subject to abnormal vibrations of said armature,and a circuit connected to said relay for locking said armature toprevent said abnormal vibration, said circuit comprising a spacedischarge device responsive to an open condition of a line connected tosaid line winding and holding means on said relay responsive to saidspace discharge device.

3. In a telegraph system, a polar telegraph signaling relay, an armatureon said relay, a line winding and a vibrating Winding on said relay, 2.line connected to said line Winding, a space discharge device connectedto said relay, said space discharge device having an input circuitconnected to said line winding and responsive to an open condition ofsaid line and an output circuit including said vibrating windingresponsive to said input circuit to hold said armature in a particularposition to prevent abnormal vibration thereof.

4. In a telegraph system, a polar telegraph signaling relay having twoline windings thereon connected in series with a telegraph line and anarmature susceptible to abnormal vibration under a particular conditionof said line, a space discharge device having a control elementconnected to the junction of said windings for impressing a potentialcharacteristic of said condition on said device to change the conditionof said device and connections between said device and said relayresponsive to said change for looking said relay.

5. In a telegraph system, a polar telegraph signaling relay having anarmature, a line winding and a vibrating winding, a line connected tosaid line winding, said armature vibrated abnormally by said vibratingwinding while a particular condition of said line prevails, an avibration prevention circuit, said circuit comprising a space dischargedevice having joint controls, said joint controls comprising a firstconnection between a first element in said device and said line winding,the potential of which connection is variable responsive to thecondition of said line windin FRANK H. HANLEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,376,248 Hanley May 14, 1946FOREIGN PATENTS Number Country Date 240,683 Great Britain Oct. 8, 1925

